Triple valve.



I J. R. SNYDER.

-TRIPLE VALVE.

APPLICATION FILED AUG. 27, 1912.

1,097,060. Patented May 19; 191 1 s SHEETS-SHEET 1. 1

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J. R. SNYDER. TRIPLE VALVE. APPLIGATIQN FILED AUG.21, 1912.

Patented May 1-9, 191i 3 SHEETS-SHEET 2.

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WITNESSES J. R. SNYDER.

TRIPLE VALVE APYLIQATION FILED AUG. 27, 1912. I I

' Patented May 19, 1914.

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JACOB RUSH SNYDER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB. TO

PERCY E.

BONNER, OF PITTSBURGH, PENNSYLVANIA.

TRIPLE VALVE.

To all 107mm it may concern:

Be it known that I, JACOB RUsI-I SNYDER, a resident of Pittsburgh, inthe county of Allegheny and State of Pennsylvania, have invented a newand useful Improvement in Triple Valves, of which the following is aspecification.

This invention relates to triple valves for air brake systems and moreparticularly for passenger car service.

The object of the invention is to provide a triple valve having all of.the usual functions of triple valves and in addition providing for aquick serial action of the brakes throughout the train, for a graduatedrelease of the brakes, for maintaining the pressure in the brakecylinder in service application against leakage, and in its preferredform also providing for the use of a pair of brake cylinders; and whichperforms these various functions by a much simpler and less complicatedconstruction than prior triple valves capable of effecting the sameresults and functions,

The invention comprises the construct-ion and arrangement of parts of atriple valve and associated elements hereinafter described and claimed.

In the accompanying drawin Figure 1 is a longitudinal section through atriple valve embodying the invention, the casing being sectioned on theline 1-1, Fig. 3, while the valves and valve seat are taken on thesection 11, Fig. 6; Fig. 2 is a transverse section taken generally onthe line 22 Fig. 1, with the main valve seat taken on the section line2-2, Fig. 6; Fig. 3 is an end view of the triple valve, the pressuremaintenance valve being omitted; Fig. 4 is a diagrammatic view showing aportion of the triple valve in horizontal section on the line 4 1, Fig.2 and showing the brake cylin ders, supplementary and auxiliary reservoirs and connections therefrom to the triple valve; Fig. 5 is a planview of the main valve seat; and Figs. 6, 7, 8, 9, 10, 11 and 12 arediagrammatic views showing the valve seat in plan and the slide valvesin horizontal section on the line (3-6, Fig. 1, and showing thedifferent positions of the Specification of Letters Patent.

Application filed August 27, 1912.

Patented May 19, 1914. SerialNo. 717,364.

valve, Fig. 6 showing the same in full release position, Fig. 7 in quickservice or quick serial application position, Fig. 8 in full serviceposition, Fig. 9 in service lap position, Fig. 10 in graduated releaseposition, Fig. 11 in graduated release lap position and Fig. 12 inemergency position.

The valve in its general form, construction and arrangement follows thestandard type of Westinghouse and similar valves. it comprises a casing1, provided at its in nor end with a fiat face 2 for the usualconnection to the auxiliary reservoir and brake cylinder if desired, andis closed at its opposite end by the head or cap 3. In said casing i thechamber 1 in which works the main'piston 5 which is provided with a stem6 extending into the bore 7 of the casing and actuating the slidevalves. In the head or cap 3 is the usual graduating stem or stop 8 heldby thegraduating spring 9 and against which the main piston abuts inservice and emergency applications as is usual. The train pipeconnection is throughtwo passages 10, one on each side of thelongitudinal center of the valve, and which meet in the common passageor chamber 11 from which a passage 12 leads through the head or cap 3and communicates with the piston chamber 4. In the bushing of pistonchamber 1 is the usual charging groove 14 which is open when the valveis in full release position and through which train pipe air passes tothe auxiliary reservoir which is connected to the end of bore 7. In thebore 7 is a suitable bushing 15, whose lowermost portion 16 forms avalve seat which is provided with the ports and passages shown in Fig.5, to

wit :A ort 17 communicating with passage 18 in the casing and whichleads to the train pipe passage 11, a check valve 19 being placed insaid connection and being seated by spring 20 toward the train pipe; aport 21 communicating with a passage 22 extending downwardly and thenlongitudinally in the casting and communicating with the larger passage23 arranged centrally and communicating with one of the brake cylindersand which will hereinafter be designated as cylinder No. 1; a port 24near the opposite end of the valve seat and communicating directly withbrake cylinder passage 23; port 25 still nearer the opposite end of thevalve seat and communicating with passage 26 to which is connected theother brake cylinder hereinafter referred to as cylinder No. 2; a port27 laterally in line with brake cylinder port 24 and longitudinally inline with port 25 and communicating with the atmosphere and forming thexhaust for the valve; a relatively small port 28 in proximity to brakecylinder port 21 and communieating with the usual reducing or blow offvalve; a small port 30 communicating with vertical passage 31 leading tothe train pipe passage 11; a small port 32 in proximity to port 31 andcommunicating through passage 33 formed in the outer face of the bushing15 and leading to a small port 3a in proximity to brake cylinder port24; a large port 36 communicating with the groove 37 cut in the outerface of the bushing 15 and ex tending part way around the same andleading to a longitudinal passage 38 in the easing and communicatingwith the supplementary reservoir; a smaller port 39 communicating withgroove %0 cut in the outer face of bushing 15 and communicating at d1with the supplementary reservoir passage 37, the ports 36 and 39therefore being supplementary reservoir ports. he port 39 can be blankedoff or rendered inoperative (which is particularly desirable when thevalve is designed to have a graduated release position to prevent thesupplementary reservoir air from reinforcing the auxiliary reservoirpressure) by means of a plug 42 threaded into the casing and having anextension 43 adapted to close one end of groove 40. hen it is desirednot to blank oii port 39, a plug 42 without the extension 43 is screwedinto the opening. From the supplementary reservoir passage 37 a passaged4 extends laterally through the casing 1 to the pressure maintenancevalve hereinafter described, and from the brake cylinder passage 22 alateral passage 4:5 also extends to said pressure maintenance valve Fig.4 shows diagrammatically the connection of this triple valve with thebrake cylinders and the auxiliary and supplementary reservoirs. As hereindicated, the end 2 of the valve casing is closed by means of cap 47provided with suitable openings for receiving the several pipes leadingto the cooperating parts, to wit: a pipe i8 communicating with brakecylinder passage 23 and leading to brake cylinder No. 1. marked 49; apipe 50 communicating with passage 26 and leading to brake cylinder No.2, marked 51; a pipe 52 communicating with the end of bore 7 and leadingto the auxiliary reservoir 53; a pipe 5e communicating with passage 38and leading to the supplementary reservoir 55, and a pipe (not shown)connecting the train pipe passages 10 with the usual train pipe. Betweenthe brake cylinders 49 and 51 is a connection 58 in which is a checkvalve 59, spring seated toward brake cylinder No. l, and between theauxiliary and supplementary reservoirs is a connection (50 in which is acheck valve ()1 spring seated toward the auxiliary reservoir.

Cooperating with the valve seat 16 are a pair of slide valves 63 and(id. The slide valve 63 is held between an end projection 65 and anintermediate projection (36 on the main valve stem 6 and substantiallyiills the space between said project-ions so that said valve 63 at alltimes moves with the piston 5. The slide valve 64: is held between theintermediate projection 66 and the shoulder 67 on the main piston stem 6but does not [ill the space between said projection and shoulder so thatthere is a certain amountof lost motion which permits the main piston tomove at times without moving the valve 6 1. These slide valves are heldto the seat by the usual springs (38.

The slide valve 63 is of the form shown in Figs; 6 to 12 being ofmodified L-shape having the main transverse portion 70 with a largelongitudinal portion 71 at one side and a smaller longitudinal portion 2on the opposite side. It is provided in its lower face with a pair ofcavities to wit: a large longitudinal cavity '73 in the mainlongitudinal portion 71 and a transverse cavity Tet in the transverseportion 70, which cavity 7% is of irregular form, shown and providednear one end with a small longitudinal extension 75. The slide valve isof rectangular form and is provided in its lower Face with a largecavity 77 of rectangular form and a smaller longitudinal cavity 78 nearone side.

The pressure maintenance valve is secured to one side of the main casing1, the latter being provided with a flange 80 to receive saidmaintenance valve which comprises a main casing portion 81 secured tothe flange 30 and having at its outer end a cap 32 and on its top aremovable cover portion 83. In the casing 81 is a suitable chamber 84-.in which works a piston 85 provided with a stem 86 whose inner endenters a guide 87 in which is a light helical spring 88. The upperportion 90 of casing 81 forms a seat for the slide valve 91 which isheld against said seat by spring 92 and which is operated by a pin 93projecting from piston stem 86 through an opening 9a in valve seat 90.The slide valve 91 operates in chamber 96 with which communicates thepassage it coming from supplementary reservoir passage 37, and saidvalve is provided with through port 97, while the valve seat is providedwith port 98 communicating with the chamber 84: and a second port 99communicating with a longitudinal passage 100 cored out in the casing 81and opening at 101 on the outer side of piston 85 for the purpose ofsupplying air at the proper time to chamber 102 in the cap 82 on theouter face of piston 85. Brake cylinder passage connects with a passage103 which opens into the chamber Set.

The piston 85 and valve 91 normally stand in neutral position, shown inFig. 2, in which position no pressure is in either the chamber 8 1 orchamber 102. In service applications, however, air flows from brakecylinder passa 'e through passages lb and 103 into chamber 84, therebyforcing the piston 85 outward or to the right, viewing Fig. 2, andbringing the port 97 in slide valve 91 into register with port 99 whichpermits air to How from the supplementary reservoir through passages 87and er, chamber 96, ports 97 and 99, and passage 100 to the chamber 102on the outer face of piston 85. as soon as this pressure equalizes withthe brake cylinder pressure on. the inner face of piston 85, the lattermoves back to neutral position, until stopped. by spring 88, therebyilanlzing the port 99 and trapping in the chamber 102 pressuresubstantially equal to that in the brake cylinder. While the main valveis in service lap position long as the pressure in the brake cylinderremains constant or substantially so, no movement of the piston 85occurs. Should, however, the brake cylinder pressure leak oliimmaterially, it correspondingly reduces pressure in the chamber 8%whereupon the superior pressure in chamber 102 forces the piston 85inwardly, compressing spring 88 and bringing port 97 of slide valve 91into register with the port 98, which permits supplementary reservoirpressure to flow through said ports 97 and 9S and through the valvechamber 8 1 to passage 103 and thence through passages 45 and 22 to thebrake cylinder. This builds up the brake cylinder pressure until itagain cqualizes with the pressure in chamber 102 when the spring 88pushes the piston 85 outwardly to blanh the port 98. If the pressureagain falls in the brake cylinder, the foregoing operation is repeatedso that said valve serves to maintain. a substantially uni. formpressure in the brake cylinder when the main valve is in service lapposition.

The connection e5 leads to brake cylinder 49, but the pressure in brakecylinder 51 is also maintained against leakage check valve 59 permitsthe flow of pressure fluid from cylinder -19 to cylinder 51. Themaintenance valve therefore, will maintain the pressure in either one orboth of the brake cylinders depending upon whether one or both isleaking.

The supplementary reservoir is charged from the auxiliary reservoirthrough the connection past the check valve 61, which check valve,however, prevents the backward flow of air, so that the air in thesupplementary reservoir is trapped whenever air is withdrawn from theauxiliary reservoir.

The valve described has seven positions as follows:

1. Full release and recharging posit-i012. (Shown in Figs. 1 and 0.)lnthis position the main piston is at its extreme inward position so as touncover feed groove 1 1 and permit air to flow from the train pipethrough passages 10, 11 and 12, chamber thence through groove 1i,through here 7 of the valve and through the pipe 52 to the auxiliaryreservoir and through the connection (30 to the supplementary reservoir,until the pressures in the auxiliary and supplementary reservoirsequalize wih the train pipe pressure. In this position,ippicmentreservoir port 39 in the valve seat 16 is uncovered so that thesupplementary reservoir is charged through this port providing thepassage 410 is not blanked oil by plug 43. In this position also thecavity 74 0 slide valve 03 connects brake cylinder port 24. with exhaustport 2'? while cavity '73 of the same slide valve connects brakecylinder port 25 with exhaust per 2?, so that both brake cylinders areexhausted. to the atmosphere. Train pipe port 17 is also uncovered sothat train pipe air can How directly to the bore 7 of the valve andthence to the supplementary and auxiliary reservoirs until the pressurein the latter, plus the tension of spring 20 equals train pipe pressurewhen valve 19 will close and thereafter the charging of the reservoirscontinues more slowly through feed groove l-i. This provides for a quickcharging of the auxiliary and supplementary reservoirs. All other portsare blanked. It is true that cavity 78 of valve 6% connects train pipeport 30 with port 32 but the connected port is covered by valve so thatno effect is produced. inasmuch as brake cylinder port 24: is connectedto the exhaust port 27 this also exhausts chamber 8 1 of the pressuremaintenance valve, and should there be any pressure in chamber 102, itdrives the piston fully over to the left. compressing spring 88 andmoving the slide valve 91 until port 97 is beyond port 98, and causingcavity 102 to connect port with the opening 9t, thereby exhausting thepressure from chamber 102, whereupon spring 88 moves the piston 85 andvalve 91 to neutrz. tion. Consequently, in full release no.

non. there is no pressure on either side of piston 85 of the pressuremaintenance valve and the connection between the supplementary reservoirand brake cylinder is blanked. v

93. Quick service or scriaZ seating position. (Shown. in Fig. 7.)Thisposition is sumed upon the first movement of the main piston upon slightreduction of train pipe (53 from the position shown in Fig. to thatshown in Fig. 7, but withoutmoving the slide valve 6% due to the lostmotion connection between the same and the main piston stem. In thisposition the feed groove 1 exhaust port 27 and Supplementary reservoirport 39 are blanked, thereby trapping the air in the supplementaryreservoir. The valve (33 is moved over so that cavity laps over port 31-, while longitudinal extension of cavity is extends over brakecylinder port 2%. This gives a directcommunication between the trainpipe and the brake cylinder through port 30, cavi y 78 in slide valve64, port 32, passage 35, port 84-, and cavity H with its extension 7:.The result is that the train pipe is momentarily vented to the brakecylinder which is at at.- niospheric pressure, thereby producing a dropin pressure in the train pipe at the car and securing a quicker serialapplication of the brakes throughout the length of the train. The effectis the same as though at each car the train pipe were momentari ventedto the atmosphere to secure quicker reduction of train pipe pressuretoward the rear of the train than would be possible it all the air hadto flow forwardly and out at the engineers brake valve. instead,however, of venting the train pipe at each car to the atmosphere it isvented into the empty brake cylinder thereby producing a light settingof the brakes. The valve remar s for a brief time in this position, dueto the fact that the first movement of the piston 5 moves only the slidevalve 63, but as soon as the slack between the piston stem (1 and theslide valve Get is taken up the greater friction encounter momentarilycheers the piston, thereby providing an appreciable time for venting thetrain pipe into the empty brake cylinder. The reduction of train pipepressure caused thereby produces a sutlicient unbalancing of pressureson the opposite sides of the main piston to oven come the friction ofboth slide valves, and the valve almost immediately moves to the nextposition now to be described.

3. Full service position. (Shown in Fig. 8.)ln this position the slidevalve has moved over sulliciently to uncover brake cylinder ports 2t and25, while blanking ex haust port 27, supplementary reservoir port 39 andvent port This allows auxiliary reservoir air to flow to both brakecylinders. The valve 04.- has blanked all ports except that it connectsbrake cyl nder port 21 with reducing valve port 28 thereby permittingall pressure in brake cylinder if) in excess or" that to which thereducing valve is set to escape to the atmosphere. Air also flows fromthe brake cylinder connection 22 through passages a5 and 103 to chamberSi in the pressure maint nance valve, thereby moving piston 85 outwardlyand bringing port 97 of slide valve 91 into register with port 09whereby supplementary reservoir pressure will flow hrough passages 37and 4A, chamber 00, ports 97 and 99 and passage 100 to chamber 102 onthe outer face of piston 85, until the pressure in said chambersubstantially balances the pressure in chamher 8% (which is equal tobrake cylinder pressure), whereupon the piston 85 moves inwardly untilits stem contacts with spring 88, thereby blanking port 99 but withoutbringing port 97 into register with port 98.

,4. Service Zap position. (Shown in Fig. 9.)This position is assumed bythe valve on the slight recoil such as occurs immediately after aservice application due to the momentary excess of pressure on the trainpipe side or" the main piston. The slide valve 0% has remainedstationary due to the lost motion connection between itself and the mainpiston stem, but the slide valve 03 has moved over sui'liciently toblank the brake cylinder ports 2-l and 25, thereby cutting off furtherflow of air from the auxiliary reservoir to the brake cylinder butmaintaining that which is already there. Should the pressure in eitherbrake cylinder leak oitl appreciably it reduces the pressure in chamber8i ot' the maintenance valve, whereby the trapped pressure in chamber102 moves the piston 85 inwardly, compressing spring 88, until port 97registers with port 08, thereby permitting supplementary reservoir airto flow through the maintenance valve to the brake cylinders and restorethe pressure therein. As soon as the brake cylinder pressure is built upto the desired degree, it reacts in chamber 84:, permitting spring 88 toexpand and move the piston 85 outwardly to neutral position and blankthe communication between the supplementary reservoir and brakecylinders. The maintenance valve will act in this manner as frequentlyas the brake cylinder pressure leaks oft appreciably, and results inmaintaining the pressure in the brake cylinders practically constantfrom the supplementary reservoirin which the pressure is still higherthan in the auxiliary reservoir which has been par J equalized into thebrake cylinders. As soon as the main valve goes to full releaseposition, the pressure in chamber 84 of the maintenance valve isentirely withdrawn, so that the piston 85 will be moved over completelyto the left, viewing Fig. 2, so that cavity 102 in slide valve 91connects pert 05) with the opening 94, thereby exhausting all pressurefrom chamber 102 and bringing the maintenance valve back to normalcondition, that is with the piston 85 and 7 valve 91 in neutral positionand no pressure on either face of said piston.

5. Graduated release position. (Shown in Fig. 10.)This position isassumed by the valve upon a slight increase of train pipe pressure aftera service application and moves the valves (53 and Get partly towardrelease position to slowly release the brakes. In this position, thevalve 64- blanks the connection between the brake cylinder port 21 andreducing valve port 28, the supplementary reservoir port 39 is partlyuncovered by slide valve 63 so that the supplementary reservoirreplenishes the auxiliary reservoir to the point of equalization withthe incr ased train pipe pressure. The cavity 74 of slide valve 63partly overlaps brake cylinder port 24 and exhaust port 27 while cavity73 partly overlaps brakecylinder port 25 and exhaust port 27, therebypermitting both brake cylinders to slowly vent to the atmos phere. Thevalve remains in this position only momentarily as the slight recoilwhich always occurs after movement of the valve, moves the same back toblank the connection between the brake cylinder ports 24: and 25 andexhaust port 27, but by again slightly increasing the train pipepressure the valve 93 can be repeatedly removed to the position shown inFig. 10 and the brakes graduated off. This sudden reduction of brakecylinder pressure reacts in chamber 84- of the maintenance valve,whereupon the su perior pressure in chamber 102 moves the piston 85 andvalve 91 inwardly until cavity 102 connects port 99 with opening 94 andpermits pressure in chamber 192 to exhaust until it equalizes with brakecylinder pressure, when spring 88 moves the piston 85 and valve 91 backto neutral position, whereupon the maintenance valve will continue tomaintain the pressure in the brake cylinder at the lower pressure.

6. Graduatedrelease Zap position. (Shown in Fig. 11.)-This position isdue to the slight recoil above referred to or by the slight increase ofauxiliary reservoir pressure over train pipe pressure due to the highpressure from the supplementary reservoir replenishing the auxiliaryreservoir by way of port 39 when the valve is in graduated releaseposition. The slide valve 6 1 has remained stationary, but the slidevalve 63 has moved suificiently to blank the connections between thebrake cylinder ports 2t and .25 and the exhaust port 27 and also blankhe supplementary reservoir port 39. If the valve is to remain in thisposition to hold the reduced brake cylinder pressure the pressuremaintenance valve will operate exactly as in service lap position tomaintain this reduced brake cylinder pressure against leakage.

7. Emergency position. (Shown in Fi 12.)This position is assumed upon alarge reduction in train pipe pressure which causes the main piston 5 tocompress the graduating spring 9 and move fully over to the left,viewing Fig. 1. In this position the eX- haust port 2'? and train pipevent port 30 are blanked as is also the port 28 leading to the reducingvalve. Both brake cylinder ports 24- and 25 are fully uncovered as arealso both supplementary reservoir ports 36 and 39 and consequently bothbrake cylinders are supplied with air from the auxiliary andsupplementary reservoirs. Cavity 77 of valve 6% also connects train pipeport 17 and brake cylinder port 21, so that train pipe pressure flowspast the check valve 19 directly to brake cylinder 49 and through theconnection 58 to brake cylinder 51. This flow of train pipe aircontinues until the brake cylinder pressure plus the tension of spring20 equals the train pipe pressure, after which the check valve 19 closesand the application is completed by equalization of the auxiliary andsupplementary reservoirs with the brake cylinders. The flow of air fromthe train pipe to the brake cylinders vents the train pipe at the car tosecure a quick serial action of the brakes throughout the train. Thehigh brake cylinder pressure in chamber 8 moves the piston 85 out wardlyto further charge chamber 102 from the supplementary reservoir. Usually,however, in emergency applications, the train pipe pressure is so lowthat the main piston remains fully over to the left irrespectiveofbrakecylinder leakage, so that usually the pressure maintenance valve willnot be 0perative but it is in position to act if the condition of thebrake cylinder requires.

The emergency position of the valve can be secured either directly fromfull release position or from any of the other positions of the valve,by merely reducing the train pipe pressure below the point of equalization of auxiliary reservoir pressure with the brake cylinder.

The valve described has all the usual functions of triple valves,including the quick service or serial venting position to secure therapid serial action of the brakes through out the train in service asWell as in emergency applications, and also the graduated release of thebrakes and means for maintaining the pressure in the brake cylindersduring service applications, in addition to the usual service andemergency application positions, as well as enabling the brakes to beheld in any of the positions by lapping the valve. The valve, therefore,performs all of the functions of the most approved triple valves but bya mechanical construction which is simpler and less complicated thanexisting valves which perform all of the functions of this valve.Consequently the valve not only is cheaper in first cost, but is morereliable in action, less liable to get out or repair, cheaper in itsupkeep, and offers less resistance to movement than similar valvescapable of securing the same functional effects.

What I claim is:

1. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure chamber, and meansactuated by pressure in said chamber for supplying pressure fluiddirectly to the brake cylinder, said means also controlling the supplyof pressure fluid to and the exhaustion of pressure fluid from saidpressure chamber.

2. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure maintenance valvecomprising a movable abutment open on one side to brake cylinderpressure, and valve mechanism actuated by said movable abutment andarranged to control the supply of pressure fluid to and the exhaustionof pressure fluid from the opposite side of said movable abutment and toalso sup ply pressure fluid directly to the brake cylinder.

3. In a fluid pressure bralre, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure maintenance valvecomprising a movable abutment open on one side to brake cylinderpressure, and valve mechanism actuated by said mov able abutment andarranged upon admission of brake cylinder pressure to one side of saidmovable abutment to supply pressure fluid to the opposite side of saidmovable abutment, on equalization of pressure on the two sides of saidmovable abutment to cut off said supply upon reduction of brake cylinderpressure on said movable abutment to open a connection from a source offluid pressure to the brake cylinder, and upon exhaustion of brakecylinder pressure to exhaust the pressure from the opposite side of saidmovable abutment.

4. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, brake cylinder and a supplementary reservoir, of apressure maintenance valve comprising a movable abutment open on oneside to brake cylinder pressure, and valve mechanism actuated by saidmovable abutment and arranged upon admission of brake cylinder pressureto one side of said movable abutment to supply pressure fluid to theopposite side of said movable abutment, on equalization of pressure onthe two sides of said movable abutment to cut ofi said supply, and uponreduction of brake cylinder pressure on said movable abutment to open aconnection from the supplementary reservoir to the brake cylinder.

5. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure maintenance valvecomprising a movable abutment open on one side to brake cylinderpressure, and valve mechanism actuated by said movable abutment andarranged upon admission of brake cylinder pressure to one side of saidmovable abutment to supply pressure fluid to the opposite side of saidmovable abutment, on equalization of pressure on the two sides of saidmovable abutment to cut off said supply, upon reduction of b akecylinder pressure on said movable abutment to open a connection from asource of pres sure fluid to the brake cylinder, and upon exhaustion ofbrake cylinder pressure on the brake cylinder side of said movableabutment to exhaust the pressure from the opposite side of said movableabutment and blank the connection from the source of pressure fluid tothe brake cylinder.

6. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, brake cylinder and a supplementary reservoir, of apressure maintenance valve comprising a movable abutment open on oneside to brake cylinder pressure, and valve mechanism actuated by saidmovable abutment and arranged upon admission of brake cylinder pressureto one side of said movable abutment to supply pressure fluid to theopposite side of said movable abutment, on equalization of pressure onthe two sides of said movable abutment to cut off said supply, uponreduction of brake cylinder pressure on said movable abutment to open aconnection from the supplementary reservoir to the brake cylinder, andupon exhaustion of brake cylinder pressure on the brake cylinder side ofsaid movable abutment to exhaust the pressure from the opposite side ofsaid movable abutment and blank the connection from the supplementaryreservoir to the brake cylinder.

7. In a fluid pressure brake, the combinatior. of a train pipe,auxiliary reservoir and brake cylinder, of a pressure maintenance valvecomprising a movable abutment open on one side to the brake cylinder,and a valve actuated by said movable abutment and arranged uponadmission of brake cylinder pressure to said movable abutment to supplyfluid pressure to the opposite side of said movable abutment and uponexhaustion of brake cylinder pressure from said movable abutment toexhaust fluid pressure from the opposite side oi said movable abutment8. In a fluid pressure brake, the combination of a train pipe, auxiliaryreservoir and brake cylinder, of a pressure maintenance valve comprisinga movable'abutment open on one side to the brake cylinder, and a valveactuated by said movable abutment and arranged when the movable abutmentis actuated by brake cylinder pressure to supply fluid pressure to theopposite side of said movable abutment and to cut of such sup ply whenthe pressures on the two sides of said movable abutment equalize, uponreduction of brake cylinder pressure on said movable abutment to open aconnection from a source of pressure fluid to the brake cylinder andupon exhaustion of brake cylinderpressure to exhaust the pressure fromthe opposite side of said movable abutment.

9. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, brake cylinder, and a supplementary reservoir, of apressure maintenance valve com prising a movable abutment open on oneside to the brake cylinder, and a valve actuated by said movableabutment and arranged when the movable abutment is actuated by brakecylinder pressure to supply fluid pressure to the opposite side of saidmovable abutment and to cut ofl such supply when the pressures on thetwo sides of said movable abutment equalize, and upon reduction of brakecylinder pressure on said movable abutment to open a connection from thesupplementary reservoir to the brake cylinder.

10. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure maintenance valvecomprising a movable abutment open on one side to the brake cylinder,and a valve actuated by said movable abutment. and arranged when themovable abutment is actuated by brake cylinder pressure to sup ply fluidpressure to the opposite side of said movable abutment and to cut ofi'such supply when the pressures on the two sides of said movable abutmentequalize, upon reduction of brake cylinder pressure on said movableabutment to open a connection from a source of pressure fluid to thebrake cylinder, and upon exhaustion of pressure on the brake cylinderside of said movable abutment to exhaust the pressure from the oppositeside or" said movable abutment and blank communication from the sourceof fluid pressure to the brake cylinder.

11. In a fluid pressure brake, the combination with train pipe,auxiliary reservoir, brake cylinder and a supplementary reservoir, of apressure maintenance valve comprising a movable abutment open on oneside to the brake cylinder, and a valve actuated by said movableabutment and arranged when the movable abutment is actuated by brakecylinder pressure to supply fluid pres sure to the opposite side of saidmovable abutment and to cut oil such supply when the pressures on thetwo sides of said movable abutment equalize, upon reduction oi brakecylinder pressure on said movable abutment to open a connection from thesup plementary reservoir to the brake cylinder,

and upon exhaustion of pressure on the brake cylinder side of saidmovable abutment to exhaust the pressure from the opposite side of saidmovable abutment and blank the connection from the supplementaryreservoir to thebrahe cylinder.

12. in a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of pressure maintenance valvecomprising amovable abutment open on one side to the brake cylinder, 21valve actuated-by said movable abutment, and a seat for said valve, saidvalve and seat being provided with ports and cavities so arranged thatactuation of said movable abutment by brake cylinder pressure openscommunication from a source of pressure fluid to the opposite side ofthe said movable abutment, upon equalization oi pressures on oppositesides of said abutment said supply is cut oli, and upon exhaustion ofbrake cylinder pressure the pressure fluid on the opposite side of saidmovable abutment is exhausted.

13. in a fluid pressure brake, the com bination with a train pipe,auxiliary reservoir and brake cylinder, oi a pressure maintenance valvecomprising a movable abutment open on one side to the brake cylinder, avalve actuated by said movabl abutment, and a seat for said valve, saidvalve and seat being provided with ports and cavities so arranged thatwhen said movable abutment actuated by brake cylinder pres surecommunication from a source of pressure fluid to the opposite side ofsaid movable abutment is opened, upon equalization of pressures onopposite sides of said abut ment said communication is cut off, uponreduction of pressure on the brake cylinder side of said movableabutment communication is established between a source of pressure fluidand the brake cylinder, and upon exhaustion of pressure on the brakecylinder side oi? said movable abutment the pressure fluid on theopposite side of said movable abutment is exhausted.

1%. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, brake cylinder and a supplementary reservoir, apressure maintenance valve com prising a movable abutment open on oneside to the brake cylinder, a valve actuated by said movable abutment,and a seat for said valve, said valve and seat being provided with portsand cavities so arranged that when said movable abutment is actuatedbrake cylinder pressure communication from a source of pressure fluid tothe opposite side said movable abutment is opened, upon equalization ofpressures on opposite sides of said abutment said communication is cutoil, and upon reduction of pressure on the brake cylinder side of saidmovable abutment communication is established between the supplementaryreservoir and the brake cylinder.

15. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir and brake cylinder, of a pressure mainteance valvecomprising a movable abutment open on one side to the brake cylinder, avalve actuated by said movable abutment, and a seat for said valve, saidvalve and seat being provided with ports and cavities so arranged thatvvhen said movable abutment is actuated by brake cylinder pressurecommunication from a source of p essure fluid to the opposite side ofsaid movable abutment is opened, upon equalization of pressures onopposite sides oi said abutment said communication is cut oil, uponreduction of pressure on the brake cylinder side of said movableabutment communication is established between a source of pressure fluidand the brake cylinder, and upon exhaustion of fluid pressure from thebrake cylinder side of said movable abutment the pressure is exhaustedfrom the opposite side of said movable abutment and the communicationfrom the source of fluid pressure to the brake cylinder is blanked.

16. In a fluid pressure brake, the combination vvith a train pipe,auxiliary reservoir, brake cylinder and a supplementary reservoir, o" apressure maintenance valve comprising a movable abutment open on oneside to the brake cylinder, valve actuated by said movable abutment, anda seat for said valve, said valve and seat being provided with ports andcavities so arranged that when said movable abutment is actuated bybrake cylinder pressure communication from a source of pressure fluid tothe opposite side of 5: id movable abutment is opened, upon equalizationof pressures on opposite sides of said abutment said communication iscut oil, upon reduction of pressure on the brake cylinder side of saidmovable abutment communication is established between the supplementaryreservoir and the brake cylinder, and upon exhaustion of fluid pressurefrom the brake cylinder side of said movable abutment the pressure isexhausted from the opposite side of said movable abutment and thecommunication from the sup plementary reservoir to the brake cylinder isblanked.

1?. la a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, brake cylinder and triple valve, of a pressuremaintenance valve comprising a movable abutment open on one side to thebrake cylinder, and valve actuated thereby, a source of fluid pressureconnected to said maintenance valve, said triple valve being arranged inservice position to open communication between the auxiliary reservoirand the brake cylinder, and the valve actu ated by said movable abutmentbeing arranged upon admission of brake cylinder pressure to one side ofsaid movable abutment to connect said source of fluid pressure to theopposite side of said movable abutment and upon diminution of pressureon the brake cylinder side of said movable abutment to connect saidsource of fluid pressure to the brake cylinder.

18. In a fluid pressure brake, the combination with a train pipe,auxiliary reservoir, a supplementary reservoir, brake cylinder andtriple valve, of a pressure maintenance valve comprising a movableabutment open on one side to the brake cylinder, and a valve actuatedthereby, connections from the supplementary reservoir to the pressuremaintenance valve, said triple valve being arranged in service positionto open communication between the auxiliary reservoir and the brakecylinder, and the valve actuated by said movable abutment being arrangedupon admission of brake cylinder pressure to one side of said movableabutment to connect the supplementary reservoir to the opposite side ofsaid movable abutment and upon diminution of pressure on the brakecylinder side of said movable abutment to connect the supplementaryreservoir to the brake cylinder.

19. In a fluid pressure brake, the combiation of a triple valve,auxiliary reservoir, tWO brake cylinders, independent connectionsbetween said brake cylinders and the triple valve, and a check valvecontrolled connection between said brake cylinders.

20. In a fluid pressure brake, the combination of a triple valve,auxiliary reservoir and UN) brake cylinders, independent connec-tionsbetween said brake cylinders and the triple valve, a pressuremaintenance valve connected to one of said cylinders and arranged tomaintain the same against leakage, a connection between the two brakecylinders, and a check valve in said connection seating toward the brakecylinder to which the pressure maintenance valve is connected.

21. In a fluid pressure brake, the combi nation of a valve devicehavingconnections to the train pipe, brake cylinder, auxiliary reservoirand atmosphere and operating by variations in train pipe pressure, apressure chamber, means arranged to admit air thereto equal to thedesired brake cylinder pressure, and a valve device actuated by thepressure in said chamber and arranged upon diminution of brake cylinderpressure to admit fluid pressure to said brake cylinder and uponexhaustion of the brake cylinder pressure to connect said pressurechamber to the atmosphere. I

In a fluid pressure brake, the combination of a va ve device havingconnections to the train pipe, brake cylinder and auxiliary reservoirand operating by variations pressure and the brake cylinder, and aspring arranged to act on said movable abutment in reinforcement of thepressure (1 5, on that side of said movable abutment open to the brakecylinder.

In testimony whereof, I have hereunto set my hand.

JACOB RUSH SNYDER.

Witnesses:

WM. P. LARKIN, MARY E. CAHooN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

